Pitman connection



April 1940- w. SCHWEMLEIN 2,198,744

PITMAN CONNECTION Filed 001;. 24, 1936 Patented Apr. 30, 1940 UNITED STATES PATENT For PITMAN CONNECTION William Schwemlein, Parkersburg, W. Va, assignor to The Parkersbnrg Rig 8; Reel Company, Parkcrsburg, W. Va., a corporation of West, Virginia Application October 24, 1936, Serial No. 107,496

3 Claims.

connection, by means of a suitable crank or wrist D pin. In actual practice, it is impossible to maintain accurate alignment between the operating parts of the apparatus referred to, the result being that in prior constructions damage and excessivewear are caused in the operation of the apparatus. I

In later constructions, this difliculty has been largely overcome by providing a connection between the pitman and the walking beam which not only permits rocking motion of the upper end 91 of thepitman on an axis parallel to the rocking axis of the walking beam,,but also permits swing ing movement of the pitman with respect to the walking beam on an axis at right angles. to the first named axis, thus permitting the walking beam to assume inaccurate or distorted positions without transmitting undue strain to the pitman. Moreover, it has been proposed to provide a pitman head construction which will permit the pitman to be readily detached from the wrist pm, "as is frequently necessary in the operation of an apparatus of this character. tachable, devices are successful for their intended purpose, but they do not provide all of the characteristics desirable in an apparatus of this char- *acter.

An important object of the present invention is to provide a novelpitman construction wherein the pitman head is readily detachable from the wrist pin structure without sacrificing any strength in the assembled elements.

A further object is to providefa novel type of self-aligning connection between the piston head and the wrist pin.

A further object is to provide a novel bearing e embodiment {of the invention. In this showing:

Such readily del Figure 1 is a sideelevation of the lower end of a pitman,

Figure 2 is a central vertical sectional View through the same,and',, I

Figure 3 is a detail perspective view of the pitman head. l

Referring to the drawing, the numeral Ill designates a pitman head as a whole having a circular lower end ll within which is an integral internal flange portion 12 having a tapered central opening I3 fora purpose to be described. The

top of the pitman head is provided with spaced riveting or welding, as will be understood. A

, bearing block [6 is provided with a peripheral face I'l tapered to correspond tothe taper of the opening is and receivable therein.

The internal flange i2 is thickened to provide a laterally extending flange 3 through which bolts 19 extend. The inner face 20 of the peripheral portion of the bearing block It lies inwardly of the plane of the adjacent face of the flange; l8, when the bearing block I6 is in operative position as shown in Figure 2. One end of each bolt l9 isthreaded into a head 2! which is then welded in positionv as at 22 to form in effect, an integral part of the bolt. Each head 2| has an engaging face contacting with the face 20 radially inwardly of the bolts IS. The opposite side of each head 2! is provided with a longitudinally extending lug 23 engaging in an annular recess Zisurrounding the flange Ill. The outer end of each bolt IE is provided with a nut 25. It will be apparent that when the nuts 25 are drawn up tight the heads 2l engage the bearing block face 29 to force the conical face ll snugly into the opening. lspproperly centered with respect thereto. The recess 24 and flange it serve to anchor the associated heads 21? against rotation as well as to steady such heads against any possible distortion. l

The bearing block it is provided in its longitudinally outer end with an axial recess 28 receiving an outer ball race 2?, the longitudinally inner end of which engages a shoulder 28 formed in the bearing block 16. The inner face of the race 23' is spherical, as indicated at E9, and the longitudinally outer end of the race 2? is flush with iile corresponding end face of the bearing block Roller. or similar bearings 30 are arrangedin the, racew2'l and run on an inner race 3!. This race surrounds the adjacent cylindrical end 32 of a wrist pin 33. The longitudinally inner extremity of the end 32 ofthe wrist pin termirnates in a shoulder 34 against which the longitudinally inner end of the inner race 3| engages.

The wrist pin is provided with a tapered portion 35 receivable in the usual opening in a conventional crank arm, a nut 36 being provided for drawing the wrist pin tightly into engagement with the crank arm. The wrist pin is provided intermediate its ends with an enlarged portion 31,

v the longitudinally inner end of which is adapted to seat against the crank arm when the apparatus is assembled. The enlarged portion of the wrist pin is provided with a peripheral groove 38 receivng a deformable packing 39 operating in an opening 40 formed in the bearing block IS.

The longitudinally outer end of the wrist pin is reduced and threaded as at 4| for reception in a nut 42 which is split at one side and adapted to be clamped against the threads 4| by a screw 43. It will be noted that the'nut 42 seats against the adjacent extremity of the wristpin end 32 and extends radially outwardly therebeyond to engage the adjacent'end of the bearing race 3i to positively maintain the latter in position. A cap 44 is arranged over the outer end of the wrist pin to protect thebearing elements against the destructive action of foreign material and the cap 44 is provided with a lubricant fitting 45. The cap 44 also is provided with aflange portion 46 secured as at 41 to the bearing block it, the flange 46 extending radially inwardly beyond the opening 26 to engage the outer race 21 to positively maintain it in position.

The operation of the device is as follows:

It will be understood that the upper end of the pitman I5 is connected to the walking beam by means of the character referred to which will permit universal movement of the pitman with respect to the walking beam. Since any desired form of universal pitman connectionmay be employed, it is believed to be unnecessary to illustrate such connection. It also will be understood that the present invention is not only adapted to be used in connection with standard rigs, but

;ing elements of the pitman, the upper end of the pitman being movable with respect to the walking beam to compensate for irregularities in movement through the use of the universal connection referred to. The pitman is also adapted to twist or to alter its angular position with respect to the axis of the wrist pin 33 because of the use of the self-aligning hearing within the bearing block H6. The spherical surface 29 obviously permits changes in the relative positions of the pitman and wrist pin, and accordingly the wrist pin is relieved of all strains except the normal loads intended to be carried thereby.

The assembly of elements is quite important not only in providing the results referred to but also in providing the necessary degree of strength and rigidity, while at the same time permitting the pitman to be disconnected from the wrist pin assembly, as is frequently necessary. Three of the bolts l9 and associated elements are preferably employed, as shown in Figure 1, although any desired number of these units may be em.- ployed. The heads 2| constitute lugs which are. operative for forcing the tapered face I! of the bearing block 5 into snug operative engagement with the tapered opening I3, whereby the pitman head and bearing block operate, in effect, as a unitary structure. Relative movement between these elements is effectively prevented by the structure referred to, and accordingly it will be [apparent that the feature of providing for the detachment of the pitman head is provided without sacrificing strength and durability.

The inner and outer bearing races 21 and 3| are effectively secured in position by the cap 44 and nut 42, respectively, the latter elements, in

operation, being rigid with the bearing block l6 and the wrist pin, respectively. The deformable packing ring 39 permits the wrist pin to alter its angular position with respect to the bearing block l6, while at the same time, such sealing ring prevents the entrance of foreign material into the bearings.

When it is desired to disconnect the pitman from the wrist pin assembly, it merely is necessary to loosen the nuts 25, turn the lugs 2| ninety degrees, and pull or tap outwardly upon the ring H of thepitman head, whereupon the universal mounting of the upper end of the pitman permits the pitman to be swung outwardly and thus completely detached from the wrist pin assembly. The parts may be assembled with equal facility by swinging the pitman head inwardly into engagement with the bearing block |5, returning the lugs 2| to their normal positions, and then tightening the nuts 25. The heads or. lugs 2| engage the bearing blockface 2| and the inwardly extending lugs 23 engage within the recess, to steady. the heads 2| and to prevent rotationthereof while the nuts 25 are being tightened.

From the foregoing it will beapparent that the present construction provides a particularly eflicient and rugged connection between a pitman and wrist pin, while providing the desirable characteristic of self-alignment. Moreover, the pitman is Very readily disconnected from the wrist pin assembly, and is so effectively connected thereto in operation as toprovide, in eifect, a unitary construction with the bearing block l6.

It is to be understood that the form of the invention herewith shown and described is .to be taken as a preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

I claim:

1. In a pitman connection, a pitman head, a wrist pin normally arranged at right angles to said pitman head, said'pitman head having a flange lying in a plane at right angles to the normal position of the axis of said wrist pin and provided with a conical opening coaxial therewith, a bearing block having a conical face fitting within said opening, circmnferentially spaced fastening elements carried by said flange and including heads engaging said block and portions of said flange to maintain said conical face in rigid engagement with said opening, said flange having a laterally extending flange through which said fastening elements extend and provided with an undercut recess engaging portions of the respective heads, and bearing means arranged between said wrist pin and said block. j

2. In a pitman connection, a pitman head having a conical opening; a bearing block having its radially outermost surface formed as a conical face engageable in said opening and having ashoulder, adjacentwthe larger end of such 5 face at right angles to the axis thereof, a wrist i pin normally coaxial with said opening and having one end arranged within said bearing block said shoulder to clamp the conical face offsaid block in said opening, theotherends of said bolt members having detachable nuts arrangedradially outwardly of said conicalopeningi ,3.Ina" pitman connection, a pitman head havinga taperedopening therein, a block having a tapered outer face corresponding in shape to and receivable in said opening, said block having a shoulder at rightangles to the axis of and adjacent, the larger end of said tapered face, a wrist, pin assembly carried by said block and comprising a wrist pin, a bearing device for supporting said wrist pin with respect to said block, and means carried by said block forsecuring said bearing device to said block, the outer face xof said block defining the radially outer-limits of said block and having all portions thereof lying radially outwardly of, said wrist pin assembly to permit its removal from said opening without disassembling said wrist pin assembly, and

clampingbolts carried by said pitman head parallel to the axis of said opening and each having portions overlying said shoulderto clamp the tapered face of said block in said opening. Y i WILLIAM SCHWEMLE IN. 

